Impact of Right Ventricular Geometry and Left Ventricular Hypertrophy on Right Ventricular Mechanics and Clinical Outcomes in Hypoplastic Left Heart Syndrome

Background - Right ventricular (RV) function is a major determinant of survival in hypoplastic left heart syndrome (HLHS). However, the relation of RV geometry to myocardial mechanics and their relation to transplant-free survival are incompletely characterized. Methods - We retrospectively studied 48 HLHS patients from the Hospital for Sick Children, Toronto, (median age, 2.2; interquartile range, 3.62 years) at different surgical stages. Patients were grouped by the presence (n = 23) or absence (n = 25) of RV “apical bulging” defined as a sigmoid-shaped septum with the RV leftward apical segment contiguous with the left ventricular (LV) lateral wall. Regional and global RV strain were measured using speckle-tracking echocardiography, and regional strains were analyzed for patterns and peak values. These were compared between HLHS anatomical subtypes and between patients with versus without apical bulging. We further investigated the association between RV geometry and dysfunction with the outcomes of heart failure, death, or transplant. Results - RV global (–7.3% ± 2.8% vs –11.2% ± 4.4%; P = .001), basal septal (–3.8% ± 3.2% vs –11.4% ± 5.8%; P = .0001) and apicolateral (–5.1% ± 3.5% vs –8.0% ± 5.8%, P = .001) longitudinal strain were lower in patients with versus without apical bulging, respectively. Apical bulging was equally prevalent in all HLHS anatomical variants. Twenty of 22 (91%) patients with apical bulging displayed hypertrophy of the LV apical and lateral segments. Death or transplantation were approximately equal in both groups but related to reduced RV global strain in patients with (seven of seven) and not in those without apical bulging (two of eight; P = .022). Conclusions - These results suggest that the finding of apical bulging is related to the presence of a hypertrophied hypoplastic LV, with a negative impact on regional and global RV function. Therefore, analysis of RV and LV geometry and mechanics may aid in the assessment and prognostication of this high-risk population

Classic pattern dyssynchrony is associated with outcome in patients with Fontan circulation

Background - Morbidity and mortality increase as Fontan patients age into adulthood. Limited studies have examined cardiac magnetic resonance and echocardiographic parameters to predict death and transplantation in children after the Fontan operation. The aim of this study was to investigate echocardiographic parameters in adolescents and adults after Fontan operation, including myocardial mechanics such as classic-pattern dyssynchrony (CPD), as predictors of transplantation or death. Methods - In a cross-sectional retrospective study, strain analysis was performed on echocardiographic studies performed between 2001 and 2015 on 110 patients with single-ventricle physiology after the Fontan procedure. Strain curves were measured and visually assessed for the presence of CPD. The primary end point was death or transplantation after a follow-up period of 85 ± 35 months after echocardiography. Results - The median age at the date of echocardiography was 20 years (range, 3-45 years). Of 110 patients, 28 had undergone transplantation. During the study period, three patients died after transplantation and seven patients died without undergoing transplantation. CPD was seen in 16 and protein-losing enteropathy in 21 of 110 patients. On multivariate analysis, CPD (hazard ratio [HR], 9.4; 95% confidence interval [CI], 2.6-34.6), protein-losing enteropathy (HR, 10.6; 95% CI, 3.4-33.2), systolic blood pressure (HR, 0.954; 95% CI, 0.913-0.996), systolic/diastolic duration ratio (HR, 6.83; 95% CI, 1.33-35.0), and E-wave deceleration time (HR, 0.98; 95% CI, 0.97-0.99) were independently associated with the primary end point. Conclusions - CPD, protein-losing enteropathy, and systolic and diastolic ventricular dysfunction are significantly associated with transplantation or death in Fontan-operated patients. In selected patients, the presence of CPD may be a basis to investigate cardiac resynchronization therapy as a treatment strategy

Genetic diversity and population structure of indigenous chicken in Rwanda using microsatellite markers

[This corrects the article DOI: 10.1371/journal.pone.0225084.]

Genetic diversity and population structure of indigenous chicken in Rwanda using microsatellite markers

Rwanda has about 4.5 million of indigenous chicken (IC) that are very low in productivity. To initiate any genetic improvement programme, IC needs to be accurately characterized. The key purpose of this study was to ascertain the genetic diversity of IC in Rwanda using microsatellite markers. Blood samples of IC sampled from 5 agro-ecological zones were collected from which DNA was extracted, amplified by PCR and genotyped using 28 microsatellite markers. A total of 325 (313 indigenous and 12 exotic) chickens were genotyped and revealed a total number of 305 alleles varying between 2 and 22 with a mean of 10.89 per locus. One hundred eighty-six (186) distinct alleles and 60 private alleles were also observed. The frequency of private alleles was highest in samples from the Eastern region, whereas those from the North West had the lowest. The influx of genes was lower in the Eastern agro-ecological zone than the North West. The mean observed heterozygosity was 0.6155, whereas the average expected heterozygosity was 0.688. The overall inbreeding coefficient among the population was 0.040. Divergence from the Hardy-Weinberg equilibrium was significant (p<0.05) in 90% of loci in all the populations. The analysis of molecular variance revealed that about 92% of the total variation originated from variation within populations. Additionally, the study demonstrated that IC in Rwanda could be clustered into four gene groups. In conclusion, there was considerable genetic diversity in IC in Rwanda, which represents a crucial genetic resource that can be conserved or optimized through genetic improvement